{{Short description|Genus of flowering plants in the amaranth family Amaranthaceae}} {{Automatic taxobox | image = Illustration Spinacia oleracea1.jpg | image_caption = ''Spinacia oleracea'' from Otto Wilhelm Thomé's 1885 ''Flora von Deutschland, Österreich und der Schweiz'' | display_parents = 2 | taxon = Spinacia | authority = L. | subdivision_ranks = Species | subdivision = *''Spinacia oleracea'' *''Spinacia tetrandra'' *''Spinacia turkestanica'' }}
'''''Spinacia''''' is a flowering plant genus in the subfamily Chenopodioideae of the family Amaranthaceae. The most common member is spinach.
== Description == The species in genus ''Spinacia'' are annual or biennial herbs. Plants are always glabrous. Their stems grow erect and are unbranched or sparsely branched. The alternate leaves consist of a petiole and a simple blade. The basal leaves are often forming a rosette. The leaf blade is triangular-hastate to ovate, sometimes with elongated lobes, with entire or dentate margins and an acute apex.<ref name="FlNAmerica" /><ref name="FlChina" />
The plants are usually dioecious, (rarely monoecious). The male flowers are in glomerules forming interrupted terminal spike-like panicles. They consist of 4-5 oblong perianth segments and 4-5 stamens. Female flowers are in glomerules sitting in the leaf axils. Enclosed by 2 accrescent or united bracteoles, without perianth, they consist of an ovary with 4-5 filiform stigmas.<ref name="FlNAmerica" /><ref name="FlChina" />
In fruit, bracteoles become enlarged and hardened, sometimes with dentate margins, sometimes several flowers becoming connate. The membranous pericarp adheres to the vertically orientated seed. The dark seed coat is spiny or smooth. The embryo is annular, surrounding the copious, farinaceous perisperm.<ref name="FlNAmerica" /><ref name="FlChina" />
The chromosome base number is x = 6, which is unusual for Chenopodioideae.<ref name="FlNAmerica" /><ref name="FlChina" />
== Distribution == The genus ''Spinacia'' was originally distributed in temperate Asia, and has been introduced to the mediterranean area early.<ref name="Uotila" /> ''Spinacia oleracea'' grows cultivated or naturalized in all temperate and subtropical regions of Europe, Asia, and North America.<ref name="GRIN" />
== Systematics == The genus ''Spinacia'' was first described in 1753 by Carl Linnaeus in ''Species Plantarum'', 2, p. 1027.<ref name="SpPl" /> Type species is ''Spinacia oleracea''. The genus name may derive from the Latin "spina" or from Persian "ispanakh" (=spine), referring to the spiny fruit.<ref name="FlNAmerica" /> ''Spinacia'' is closely related to genus ''Blitum'', both grouping in Tribus Anserineae (Syn. Spinacieae).<ref name="Fuentes 2012" />
The genus ''Spinacia'' comprises 3 species: * ''Spinacia oleracea'' L., spinach: only cultivated, probably originating from Southwest Asia.<ref name="GRIN" /> * ''Spinacia tetrandra'' Steven ex M. Bieb.: in Caucasus region (Armenia, Azerbaijan) and Western Asia (Iran, Iraq, Jordan, Syria, eventually Turkey).<ref name="GRIN" /> * ''Spinacia turkestanica'' Iljin: in Western Asia (Iran) and Middle Asia (Afghanistan, Kazakhstan, Turkmenistan, southern Russia, Pakistan, India, Tibet).<ref name="Uotila" />
==References== {{Commons category|Spinacia}} {{Wikispecies|Spinacia}} <references> <ref name="FlNAmerica">Leila M. Shultz: [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=131008 ''Spinacia'', p. 302 - online] In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico. Volume 4: Magnoliophyta: Caryophyllidae, part 1. Oxford University Press, New York u.a. 2003, {{ISBN|0-19-517389-9}}.</ref> <ref name="FlChina">Gelin Zhu, Sergei L. Mosyakin & Steven E. Clemants: ''Chenopodiaceae'': [http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=131008 ''Spinacia'', p. 366 - online], In: Wu Zhengyi, Peter H. Raven, Deyuan Hong (Ed.): ''Flora of China'', Volume 5: ''Ulmaceae through Basellaceae.'', Science Press und Missouri Botanical Garden Press, Beijing und St. Louis, 2003, {{ISBN|1-930723-27-X}}.</ref> <ref name="Fuentes 2012">Susy Fuentes-Bazan, Pertti Uotila, Thomas Borsch: ''A novel phylogeny-based generic classification for Chenopodium sensu lato, and a tribal rearrangement of Chenopodioideae (Chenopodiaceae).'' In: ''Willdenowia.'' Vol. 42, No. 1, 2012, p. 16.</ref> <ref name="GRIN">[http://www.ars-grin.gov/cgi-bin/npgs/html/genus.pl?11405 ''Spinacia''], ''Germplasm Resources Information Network'' - (GRIN) [Online Database], accessed 2013-07-10.</ref> .<ref name="SpPl">[https://www.biodiversitylibrary.org/page/359048 ''Species plantarum'' at BHL]</ref> <ref name="Uotila">Pertti Uotila: ''Spinacia''. In: Karl Heinz Rechinger et al. (Ed.): Flora Iranica, Vol. 172 - Chenopodiaceae. Graz, Akad. Druck, 1997, p.59-63.</ref> </references>
{{Taxonbar|from=Q148968}} {{Authority control}}
Category:Chenopodioideae Category:Amaranthaceae genera Category:Dioecious plants